<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
      <button type="button">普通的按钮</button>
      <hr>
      <form action="" method="GET" name='one_form'>
        <label for="">用户名:</label>
        <input type="text" id='username'><br>
        <label for="">密码</label>
        <input type="password" id='pwd'><br>
        <button type="submit">提交</button>
      </form>
    
</body>
</html>
<script>
    /*
     js操作表单：
        
      1 如何获得表单：   document.one_from
       
    */

   let formObj = document.getElementsByTagName('form')[0];

   console.log(formObj);


</script>